Single-Step Substitution of all the α, β-Positions in Pyrrole: Choice of Binuclear versus Multinuclear Complex of the Novel Polydentate Ligand

2014 ◽  
Vol 53 (8) ◽  
pp. 4117-4129 ◽  
Author(s):  
Debasish Ghorai ◽  
Ganesan Mani
Keyword(s):  
Single Step ◽  
The Novel ◽  
Polydentate Ligand ◽  
Multinuclear Complex

scholarly journals Novel late-stage radiosynthesis of 5-[18F]-trifluoromethyl-1,2,4-oxadiazole (TFMO) containing molecules for PET imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nashaat Turkman ◽  
Daxing Liu ◽  
Isabella Pirola
Keyword(s):  
Late Stage ◽  
Histone Deacetylases ◽  
Radiochemical Purity ◽  
Radiochemical Yield ◽  
Single Step ◽  
The Novel ◽  
Molar Activity ◽  
The Central Nervous System ◽  
Class Iia Hdacs ◽  
18F Fluoride

AbstractSmall molecules that contain the (TFMO) moiety were reported to specifically inhibit the class-IIa histone deacetylases (HDACs), an important target in cancer and the disorders of the central nervous system (CNS). However, radiolabeling methods to incorporate the [18F]fluoride into the TFMO moiety are lacking. Herein, we report a novel late-stage incorporation of [18F]fluoride into the TFMO moiety in a single radiochemical step. In this approach the bromodifluoromethyl-1,2,4-oxadiazole was converted into [18F]TFMO via no-carrier-added bromine-[18F]fluoride exchange in a single step, thus producing the PET tracers with acceptable radiochemical yield (3–5%), high radiochemical purity (> 98%) and moderate molar activity of 0.33–0.49 GBq/umol (8.9–13.4 mCi/umol). We validated the utility of the novel radiochemical design by the radiosynthesis of [18F]TMP195, which is a known TFMO containing potent inhibitor of class-IIa HDACs.

scholarly journals Biosensing Membrane Base on Ferulic Acid and Glucose Oxidase for an Amperometric Glucose Biosensor

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3757
Author(s):  
Gabriela Valdés-Ramírez ◽  
Laura Galicia
Keyword(s):  
Ferulic Acid ◽  
Glucose Oxidase ◽  
Aqueous Media ◽  
Glucose Biosensor ◽  
Single Step ◽  
Coefficient Of Determination ◽  
The Novel ◽  
Carbon Paste ◽  
Glucose Response ◽  
Glucose Biosensors

A biosensing membrane base on ferulic acid and glucose oxidase is synthesized onto a carbon paste electrode by electropolymerization via cyclic voltammetry in aqueous media at neutral pH at a single step. The developed biosensors exhibit a linear response from 0.082 to 34 mM glucose concentration, with a coefficient of determination R2 equal to 0.997. The biosensors display a sensitivity of 1.1 μAmM−1 cm−2, a detection limit of 0.025 mM, and 0.082 mM as glucose quantification limit. The studies reveal stable, repeatable, and reproducible biosensors response. The results indicate that the novel poly-ferulic acid membrane synthesized by electropolymerization is a promising method for glucose oxidase immobilization towards the development of glucose biosensors. The developed glucose biosensors exhibit a broader linear glucose response than other polymer-based glucose biosensors.

scholarly journals Mechanisms and Frequency of Resistance to Premafloxacin in Staphylococcus aureus: Novel Mutations Suggest Novel Drug-Target Interactions

2000 ◽  
Vol 44 (12) ◽  
pp. 3344-3350 ◽  
Author(s):  
Dilek Ince ◽  
David C. Hooper
Keyword(s):  
Staphylococcus Aureus ◽  
Fold Increase ◽  
Single Step ◽  
The Novel ◽  
Novel Mutations ◽  
Topoisomerase Iv ◽  
Double Mutation ◽  
Fourfold Increase ◽  
Novel Drug

ABSTRACT Premafloxacin is a novel 8-methoxy fluoroquinolone with enhanced activity against Staphylococcus aureus. We found premafloxacin to be 32-fold more active than ciprofloxacin against wild-type S. aureus. Single mutations in either subunit of topoisomerase IV caused a four- to eightfold increase in the MICs of both quinolones. A double mutation (gyrA and eithergrlA or grlB) caused a 32-fold increase in the MIC of premafloxacin, while the MIC of ciprofloxacin increased 128-fold. Premafloxacin appeared to be a poor substrate for NorA, with NorA overexpression causing an increase of twofold or less in the MIC of premafloxacin in comparison to a fourfold increase in the MIC of ciprofloxacin. The frequency of selection of resistant mutants was 6.4 × 10−10 to 4.0 × 10−7 at twofold the MIC of premafloxacin, 2 to 4 log10 less than that with ciprofloxacin. Single-step mutants could not be selected at higher concentrations of premafloxacin. In five single-step mutants, only one previously described uncommon mutation (Ala116Glu), and four novel mutations (Arg43Cys, Asp69Tyr, Ala176Thr, and Pro157Leu), three of which were outside the quinolone resistance-determining region (QRDR) were found. Genetic linkage studies, in which incross ofgrlA + and outcross of mutations were performed, showed a high correlation between the mutations and the resistance phenotypes, and allelic exchange experiments confirmed the role of the novel mutations in grlA in resistance. Our results suggest that although topoisomerase IV is the primary target of premafloxacin, premafloxacin appears to interact with topoisomerase IV in a manner different from that of other quinolones and that the range of the QRDR of grlA should be expanded.

scholarly journals Dual Targeting of DNA Gyrase and Topoisomerase IV: Target Interactions of Garenoxacin (BMS-284756, T-3811ME), a New Desfluoroquinolone

2002 ◽  
Vol 46 (11) ◽  
pp. 3370-3380 ◽  
Author(s):  
Dilek Ince ◽  
Xiamei Zhang ◽  
L. Christine Silver ◽  
David C. Hooper
Keyword(s):  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Fold Increase ◽  
Single Step ◽  
The Novel ◽  
Wild Type ◽  
Topoisomerase Iv ◽  
Dual Targeting ◽  
Resistant Mutants ◽  
Selection Of

ABSTRACT We determined the target enzyme interactions of garenoxacin (BMS-284756, T-3811ME), a novel desfluoroquinolone, in Staphylococcus aureus by genetic and biochemical studies. We found garenoxacin to be four- to eightfold more active than ciprofloxacin against wild-type S. aureus. A single topoisomerase IV or gyrase mutation caused only a 2- to 4-fold increase in the MIC of garenoxacin, whereas a combination of mutations in both loci caused a substantial increase (128-fold). Overexpression of the NorA efflux pump had minimal effect on resistance to garenoxacin. With garenoxacin at twice the MIC, selection of resistant mutants (<7.4 × 10−12 to 4.0 × 10−11) was 5 to 6 log units less than that with ciprofloxacin. Mutations inside or outside the quinolone resistance-determining regions (QRDR) of either topoisomerase IV, or gyrase, or both were selected in single-step mutants, suggesting dual targeting of topoisomerase IV and gyrase. Three of the novel mutations were shown by genetic experiments to be responsible for resistance. Studies with purified topoisomerase IV and gyrase from S. aureus also showed that garenoxacin had similar activity against topoisomerase IV and gyrase (50% inhibitory concentration, 1.25 to 2.5 and 1.25 μg/ml, respectively), and although its activity against topoisomerase IV was 2-fold greater than that of ciprofloxacin, its activity against gyrase was 10-fold greater. This study provides the first genetic and biochemical data supporting the dual targeting of topoisomerase IV and gyrase in S. aureus by a quinolone as well as providing genetic proof for the expansion of the QRDRs to include the 5′ terminus of grlB and the 3′ terminus of gyrA.

Convergence for the optimal control problems using collocation at Legendre-Gauss points

2021 ◽  
pp. 014233122110433
Author(s):  
Heng Mai
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Shooting Method ◽  
Pseudospectral Method ◽  
Single Step ◽  
The Novel ◽  
Step Method ◽  
Gauss Method ◽  
Gauss Points

The convergence of the novel Legendre-Gauss method is established for solving a continuous optimal control problem using collocation at Legendre-Gauss points. The method allows for changes in the number of Legendre-Gauss points to meet the error tolerance. The continuous optimal control problem is first discretized into a nonlinear programming problem at Gauss collocations by the Legendre-Gauss method. Subsequently, we prove the convergence of the Legendre-Gauss algorithm under the assumption that the continuous optimal control problem has a smooth solution. Compared with those of the shooting method, the single step method, and the general pseudospectral method, the numerical example shows that the Legendre-Gauss method has higher computational efficiency and accuracy in solving the optimal control problem.

scholarly journals Fast and Fair Handling of Multimedia CAPTCHA Flows

2015 ◽  
Vol 9 (4) ◽  
pp. 64 ◽  
Author(s):  
Ageliki N Tsioliaridou ◽  
Chi Zhang ◽  
Christos K Liaskos
Keyword(s):  
Crucial Role ◽  
High Efficiency ◽  
Control Mechanism ◽  
Network Flows ◽  
Single Step ◽  
Convergence Speed ◽  
Transport Layer ◽  
The Novel ◽  
High Transmission ◽  
Transmission Quality

Multimedia CAPTCHAs play a crucial role in bot filtering policies for VoIP applications. Network flows carrying CAPTCHA content have a very small lifespan and require high transmission quality, making for special handling at transport layer. The present study introduces an analysis-derived, rapidly converging control mechanism for CAPTCHA flows. Instead of relying on generic heuristics, the novel scheme enables the flows to estimate their deviation from the equilibrium and adapt to it in a single step. Simulations demonstrate the high efficiency and convergence speed of the scheme, highlighting its unique fitness for the appointed task.

scholarly journals Detection and Differentiation of Chlamydiae by Fluorescence In Situ Hybridization

2002 ◽  
Vol 68 (8) ◽  
pp. 4081-4089 ◽  
Author(s):  
Sven Poppert ◽  
Andreas Essig ◽  
Reinhard Marre ◽  
Michael Wagner ◽  
Matthias Horn
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Single Step ◽  
Detection Methods ◽  
The Novel ◽  
Antibody Staining ◽  
Uncultured Bacteria ◽  
Direct Fluorescence ◽  
Probe Set

ABSTRACT Chlamydiae are important pathogens of humans and animals but diagnosis of chlamydial infections is still hampered by inadequate detection methods. Fluorescence in situ hybridization (FISH) using rRNA-targeted oligonucleotide probes is widely used for the investigation of uncultured bacteria in complex microbial communities and has recently also been shown to be a valuable tool for the rapid detection of various bacterial pathogens in clinical specimens. Here we report on the development and evaluation of a hierarchic probe set for the specific detection and differentiation of chlamydiae, particularly C. pneumoniae, C. trachomatis, C. psittaci, and the recently described chlamydia-like bacteria comprising the novel genera Neochlamydia and Parachlamydia. The specificity of the nine newly developed probes was successfully demonstrated by in situ hybridization of experimentally infected amoebae and HeLa 229 cells, including HeLa 229 cells coinfected with C. pneumoniae and C. trachomatis. FISH reliably stained chlamydial inclusions as early as 12 h postinfection. The sensitivity of FISH was further confirmed by combination with direct fluorescence antibody staining. In contrast to previously established detection methods for chlamydiae, FISH was not susceptible to false-positive results and allows the detection of all recognized chlamydiae in one single step.

A Multifunctional Reagent Designed for the Site-Selective Amination of Pyridines

2020 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Ryan Cohen
Keyword(s):  
Reaction Mechanism ◽  
Direct Conversion ◽  
Single Step ◽  
The Novel ◽  
Title Reaction ◽  
Mild Conditions ◽  
Unique Reaction ◽  
Unexpected Findings ◽  
Site Selective

We report the development of a multifunctional reagent for the direct conversion of pyridines to Boc-protected 2-aminopyridines with exquisite site- and chemoselectivity. The novel reagent was prepared on 200 gram-scale in a single step, reacts in the title reaction under mild conditions without precautions towards air or moisture, and is tolerant of nearly all common functionality. Experimental and <i>in-situ </i>spectroscopic<i> </i>monitoring techniques provide detailed insights and unexpected findings for the unique reaction mechanism.

From Single Molecules to Nanoscopically Structured Functional Materials

2006 ◽  
Vol 988 ◽  
Author(s):  
Wolfgang Tremel ◽  
Helen Annal Therese ◽  
Muhammad Nawaz Tahir ◽  
Nicole Zink ◽  
Marc Eberhardt ◽  
...  
Keyword(s):  
High Temperature ◽  
Functional Materials ◽  
Nitrilotriacetic Acid ◽  
Single Step ◽  
The Novel ◽  
Reactive Polymer ◽  
High Temperature Reaction ◽  
Step Procedure ◽  
Annealing Step ◽  
One Step

AbstractThe synthesis of MS2 (M = Mo, W) onion-like nanoparticles by means of a high temperature MOCVD process starting from W(CO)6 and elemental sulfur is reported. The reaction can also be carried out in two steps where the intermediate amorphous WS2 nanoparticles formed through the high temperature reaction of tungsten and sulfur in the initial phase of the reaction are isolated and converted in a separate annealing step to onion-type WS2 nanoparticles. Based on a study of the temperature dependence of the reaction a set of conditions could be derived where onion-like structures were formed in a one-step reaction. Onion-like structures obtained in the single-step process were filled, whereas the particles obtained by the two-step procedure were systematically hollow. A model could be devised to rationalize the different outcome of the reactions. The MOCVD approach therefore allows a selective synthesis of open and filled fullerene-like chalcogenide nanoparticles. Furthermore, we demonstrate the novel surface functionalization of WS2 nanotubes with polymeric ligands by complexation with a combination of Ni2+ via an scorpionate-type nitrilotriacetic acid (NTA) and immobilization of TiO2 nanoparticles onto the surface of nanotubes. Synthesis of such a functional polymeric ligand was achieved via a reactive polymer precursor route.

ChemInform Abstract: Reaction of 1-Diethylaminopropyne (II) with Difunctionalized 4- Nitroisoxazoles (I). A Single Step Access to the Novel Isoxazolo(4,3-c) isoxazole (III) System.

ChemInform ◽  
2010 ◽  
Vol 23 (27) ◽  
pp. no-no
Author(s):  
R. NESI ◽  
D. GIOMI ◽  
S. PAPALEO ◽  
S. TURCHI ◽  
P. DAPPORTO ◽  
...  
Keyword(s):  
Single Step ◽  
The Novel
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